release/src-rt-6.x.4708/linux/linux-2.6.36/fs/hfs/btree.c

   1 /*
   2  *  linux/fs/hfs/btree.c
   3  *
   4  * Copyright (C) 2001
   5  * Brad Boyer (flar@allandria.com)
   6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   7  *
   8  * Handle opening/closing btree
   9  */
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/slab.h>
  13 #include <linux/log2.h>
  14
  15 #include "btree.h"
  16
  17 /* Get a reference to a B*Tree and do some initial checks */
  18 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id, btree_keycmp keycmp)
  19 {
  20         struct hfs_btree *tree;
  21         struct hfs_btree_header_rec *head;
  22         struct address_space *mapping;
  23         struct page *page;
  24         unsigned int size;
  25
  26         tree = kzalloc(sizeof(*tree), GFP_KERNEL);
  27         if (!tree)
  28                 return NULL;
  29
  30         init_MUTEX(&tree->tree_lock);
  31         spin_lock_init(&tree->hash_lock);
  32         /* Set the correct compare function */
  33         tree->sb = sb;
  34         tree->cnid = id;
  35         tree->keycmp = keycmp;
  36
  37         tree->inode = iget_locked(sb, id);
  38         if (!tree->inode)
  39                 goto free_tree;
  40         BUG_ON(!(tree->inode->i_state & I_NEW));
  41         {
  42         struct hfs_mdb *mdb = HFS_SB(sb)->mdb;
  43         HFS_I(tree->inode)->flags = 0;
  44         mutex_init(&HFS_I(tree->inode)->extents_lock);
  45         switch (id) {
  46         case HFS_EXT_CNID:
  47                 hfs_inode_read_fork(tree->inode, mdb->drXTExtRec, mdb->drXTFlSize,
  48                                     mdb->drXTFlSize, be32_to_cpu(mdb->drXTClpSiz));
  49                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
  50                 break;
  51         case HFS_CAT_CNID:
  52                 hfs_inode_read_fork(tree->inode, mdb->drCTExtRec, mdb->drCTFlSize,
  53                                     mdb->drCTFlSize, be32_to_cpu(mdb->drCTClpSiz));
  54                 tree->inode->i_mapping->a_ops = &hfs_btree_aops;
  55                 break;
  56         default:
  57                 BUG();
  58         }
  59         }
  60         unlock_new_inode(tree->inode);
  61
  62         if (!HFS_I(tree->inode)->first_blocks) {
  63                 printk(KERN_ERR "hfs: invalid btree extent records (0 size).\n");
  64                 goto free_inode;
  65         }
  66
  67         mapping = tree->inode->i_mapping;
  68         page = read_mapping_page(mapping, 0, NULL);
  69         if (IS_ERR(page))
  70                 goto free_inode;
  71
  72         /* Load the header */
  73         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
  74         tree->root = be32_to_cpu(head->root);
  75         tree->leaf_count = be32_to_cpu(head->leaf_count);
  76         tree->leaf_head = be32_to_cpu(head->leaf_head);
  77         tree->leaf_tail = be32_to_cpu(head->leaf_tail);
  78         tree->node_count = be32_to_cpu(head->node_count);
  79         tree->free_nodes = be32_to_cpu(head->free_nodes);
  80         tree->attributes = be32_to_cpu(head->attributes);
  81         tree->node_size = be16_to_cpu(head->node_size);
  82         tree->max_key_len = be16_to_cpu(head->max_key_len);
  83         tree->depth = be16_to_cpu(head->depth);
  84
  85         size = tree->node_size;
  86         if (!is_power_of_2(size))
  87                 goto fail_page;
  88         if (!tree->node_count)
  89                 goto fail_page;
  90         switch (id) {
  91         case HFS_EXT_CNID:
  92                 if (tree->max_key_len != HFS_MAX_EXT_KEYLEN) {
  93                         printk(KERN_ERR "hfs: invalid extent max_key_len %d\n",
  94                                 tree->max_key_len);
  95                         goto fail_page;
  96                 }
  97                 break;
  98         case HFS_CAT_CNID:
  99                 if (tree->max_key_len != HFS_MAX_CAT_KEYLEN) {
 100                         printk(KERN_ERR "hfs: invalid catalog max_key_len %d\n",
 101                                 tree->max_key_len);
 102                         goto fail_page;
 103                 }
 104                 break;
 105         default:
 106                 BUG();
 107         }
 108
 109         tree->node_size_shift = ffs(size) - 1;
 110         tree->pages_per_bnode = (tree->node_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 111
 112         kunmap(page);
 113         page_cache_release(page);
 114         return tree;
 115
 116 fail_page:
 117         page_cache_release(page);
 118 free_inode:
 119         tree->inode->i_mapping->a_ops = &hfs_aops;
 120         iput(tree->inode);
 121 free_tree:
 122         kfree(tree);
 123         return NULL;
 124 }
 125
 126 /* Release resources used by a btree */
 127 void hfs_btree_close(struct hfs_btree *tree)
 128 {
 129         struct hfs_bnode *node;
 130         int i;
 131
 132         if (!tree)
 133                 return;
 134
 135         for (i = 0; i < NODE_HASH_SIZE; i++) {
 136                 while ((node = tree->node_hash[i])) {
 137                         tree->node_hash[i] = node->next_hash;
 138                         if (atomic_read(&node->refcnt))
 139                                 printk(KERN_ERR "hfs: node %d:%d still has %d user(s)!\n",
 140                                         node->tree->cnid, node->this, atomic_read(&node->refcnt));
 141                         hfs_bnode_free(node);
 142                         tree->node_hash_cnt--;
 143                 }
 144         }
 145         iput(tree->inode);
 146         kfree(tree);
 147 }
 148
 149 void hfs_btree_write(struct hfs_btree *tree)
 150 {
 151         struct hfs_btree_header_rec *head;
 152         struct hfs_bnode *node;
 153         struct page *page;
 154
 155         node = hfs_bnode_find(tree, 0);
 156         if (IS_ERR(node))
 157                 /* panic? */
 158                 return;
 159         /* Load the header */
 160         page = node->page[0];
 161         head = (struct hfs_btree_header_rec *)(kmap(page) + sizeof(struct hfs_bnode_desc));
 162
 163         head->root = cpu_to_be32(tree->root);
 164         head->leaf_count = cpu_to_be32(tree->leaf_count);
 165         head->leaf_head = cpu_to_be32(tree->leaf_head);
 166         head->leaf_tail = cpu_to_be32(tree->leaf_tail);
 167         head->node_count = cpu_to_be32(tree->node_count);
 168         head->free_nodes = cpu_to_be32(tree->free_nodes);
 169         head->attributes = cpu_to_be32(tree->attributes);
 170         head->depth = cpu_to_be16(tree->depth);
 171
 172         kunmap(page);
 173         set_page_dirty(page);
 174         hfs_bnode_put(node);
 175 }
 176
 177 static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 178 {
 179         struct hfs_btree *tree = prev->tree;
 180         struct hfs_bnode *node;
 181         struct hfs_bnode_desc desc;
 182         __be32 cnid;
 183
 184         node = hfs_bnode_create(tree, idx);
 185         if (IS_ERR(node))
 186                 return node;
 187
 188         if (!tree->free_nodes)
 189                 panic("FIXME!!!");
 190         tree->free_nodes--;
 191         prev->next = idx;
 192         cnid = cpu_to_be32(idx);
 193         hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
 194
 195         node->type = HFS_NODE_MAP;
 196         node->num_recs = 1;
 197         hfs_bnode_clear(node, 0, tree->node_size);
 198         desc.next = 0;
 199         desc.prev = 0;
 200         desc.type = HFS_NODE_MAP;
 201         desc.height = 0;
 202         desc.num_recs = cpu_to_be16(1);
 203         desc.reserved = 0;
 204         hfs_bnode_write(node, &desc, 0, sizeof(desc));
 205         hfs_bnode_write_u16(node, 14, 0x8000);
 206         hfs_bnode_write_u16(node, tree->node_size - 2, 14);
 207         hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
 208
 209         return node;
 210 }
 211
 212 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 213 {
 214         struct hfs_bnode *node, *next_node;
 215         struct page **pagep;
 216         u32 nidx, idx;
 217         unsigned off;
 218         u16 off16;
 219         u16 len;
 220         u8 *data, byte, m;
 221         int i;
 222
 223         while (!tree->free_nodes) {
 224                 struct inode *inode = tree->inode;
 225                 u32 count;
 226                 int res;
 227
 228                 res = hfs_extend_file(inode);
 229                 if (res)
 230                         return ERR_PTR(res);
 231                 HFS_I(inode)->phys_size = inode->i_size =
 232                                 (loff_t)HFS_I(inode)->alloc_blocks *
 233                                 HFS_SB(tree->sb)->alloc_blksz;
 234                 HFS_I(inode)->fs_blocks = inode->i_size >>
 235                                           tree->sb->s_blocksize_bits;
 236                 inode_set_bytes(inode, inode->i_size);
 237                 count = inode->i_size >> tree->node_size_shift;
 238                 tree->free_nodes = count - tree->node_count;
 239                 tree->node_count = count;
 240         }
 241
 242         nidx = 0;
 243         node = hfs_bnode_find(tree, nidx);
 244         if (IS_ERR(node))
 245                 return node;
 246         len = hfs_brec_lenoff(node, 2, &off16);
 247         off = off16;
 248
 249         off += node->page_offset;
 250         pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 251         data = kmap(*pagep);
 252         off &= ~PAGE_CACHE_MASK;
 253         idx = 0;
 254
 255         for (;;) {
 256                 while (len) {
 257                         byte = data[off];
 258                         if (byte != 0xff) {
 259                                 for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
 260                                         if (!(byte & m)) {
 261                                                 idx += i;
 262                                                 data[off] |= m;
 263                                                 set_page_dirty(*pagep);
 264                                                 kunmap(*pagep);
 265                                                 tree->free_nodes--;
 266                                                 mark_inode_dirty(tree->inode);
 267                                                 hfs_bnode_put(node);
 268                                                 return hfs_bnode_create(tree, idx);
 269                                         }
 270                                 }
 271                         }
 272                         if (++off >= PAGE_CACHE_SIZE) {
 273                                 kunmap(*pagep);
 274                                 data = kmap(*++pagep);
 275                                 off = 0;
 276                         }
 277                         idx += 8;
 278                         len--;
 279                 }
 280                 kunmap(*pagep);
 281                 nidx = node->next;
 282                 if (!nidx) {
 283                         printk(KERN_DEBUG "hfs: create new bmap node...\n");
 284                         next_node = hfs_bmap_new_bmap(node, idx);
 285                 } else
 286                         next_node = hfs_bnode_find(tree, nidx);
 287                 hfs_bnode_put(node);
 288                 if (IS_ERR(next_node))
 289                         return next_node;
 290                 node = next_node;
 291
 292                 len = hfs_brec_lenoff(node, 0, &off16);
 293                 off = off16;
 294                 off += node->page_offset;
 295                 pagep = node->page + (off >> PAGE_CACHE_SHIFT);
 296                 data = kmap(*pagep);
 297                 off &= ~PAGE_CACHE_MASK;
 298         }
 299 }
 300
 301 void hfs_bmap_free(struct hfs_bnode *node)
 302 {
 303         struct hfs_btree *tree;
 304         struct page *page;
 305         u16 off, len;
 306         u32 nidx;
 307         u8 *data, byte, m;
 308
 309         dprint(DBG_BNODE_MOD, "btree_free_node: %u\n", node->this);
 310         tree = node->tree;
 311         nidx = node->this;
 312         node = hfs_bnode_find(tree, 0);
 313         if (IS_ERR(node))
 314                 return;
 315         len = hfs_brec_lenoff(node, 2, &off);
 316         while (nidx >= len * 8) {
 317                 u32 i;
 318
 319                 nidx -= len * 8;
 320                 i = node->next;
 321                 hfs_bnode_put(node);
 322                 if (!i) {
 323                         /* panic */;
 324                         printk(KERN_CRIT "hfs: unable to free bnode %u. bmap not found!\n", node->this);
 325                         return;
 326                 }
 327                 node = hfs_bnode_find(tree, i);
 328                 if (IS_ERR(node))
 329                         return;
 330                 if (node->type != HFS_NODE_MAP) {
 331                         /* panic */;
 332                         printk(KERN_CRIT "hfs: invalid bmap found! (%u,%d)\n", node->this, node->type);
 333                         hfs_bnode_put(node);
 334                         return;
 335                 }
 336                 len = hfs_brec_lenoff(node, 0, &off);
 337         }
 338         off += node->page_offset + nidx / 8;
 339         page = node->page[off >> PAGE_CACHE_SHIFT];
 340         data = kmap(page);
 341         off &= ~PAGE_CACHE_MASK;
 342         m = 1 << (~nidx & 7);
 343         byte = data[off];
 344         if (!(byte & m)) {
 345                 printk(KERN_CRIT "hfs: trying to free free bnode %u(%d)\n", node->this, node->type);
 346                 kunmap(page);
 347                 hfs_bnode_put(node);
 348                 return;
 349         }
 350         data[off] = byte & ~m;
 351         set_page_dirty(page);
 352         kunmap(page);
 353         hfs_bnode_put(node);
 354         tree->free_nodes++;
 355         mark_inode_dirty(tree->inode);
 356 }